Well I've finished playing with my McLaren for the night and it's still in one piece and going strong. I smacked it up against the wall more times than I'd like... unintentionally, of course,
and managed to run it under my oven once and it's still going strong with no sign of damage, yet. Again, I would NOT, I repeat, NOT recommend bouncing them off walls. I'm sure it would just be a matter of time before something would give. For my future F1 racing circuit "excursions", I plan to put foam tubing around the perimeters for protection.
I feel fortunate my friend was able to find them at all and I'm grateful he got them for me. He didn't have time for comparison shopping and considering that I didn't have to pay international shipping charges to get them to me, I'm not concerned he didn't find the lowest possible price.